The present invention generally relates to hand tools and more particularly to an apparatus for preventing disengagement of an axially moveable and rotatable flexible core member of a flexible shaft attachment of the type which has a handpiece on one end, and its other end is coupled to a rotary hand tool.
There has been continued innovation and improvement in the design of power tools, particularly rotary hand tools of the type that are used in woodworking, metal working and the like. Examples of such products are those produced under the Dremel brand by the S-B Power Tool Corporation of Chicago, Ill., which also produces many accessory attachments for such rotary hand tools. The rotary hand tools are generally cylindrical in shape and have a motorized drive unit with a rotary output shaft that is adapted to drive the various rotary tools, such as small saw blades, sander discs, grout removal tools and various shaped cutting tool bits. There are also many accessory attachments that can be used in association with the rotary tools, with the accessory attachments being connected to the stationary nose end portion of the rotary tool via a coupling apparatus. Among such accessory attachments is a flexible shaft attachment that conveniently allows the user to operate the various rotary tool bits around corners or in other remote areas of operation.
While such flexible shaft attachments have been available for many years, the manner in which the flexible shaft attachments are coupled to the tool has been the subject of continuing efforts to provide a simple and effective mechanism for preventing the disengagement of the flexible core member from the handpiece. Thus, the manner in which flexible shaft attachments are presently coupled to rotary tools, while effective, does not prevent disengagement of the flexible core member from the handpiece end under some operating circumstances.
The present invention is related to a particularly simple and convenient stop plug apparatus for preventing disengagement of the axially moveable and rotatable flexible core member of a flexible shaft attachment from the handpiece end during use. The present invention comprises a stop plug apparatus that enables a user to operate a flexible shaft attachment having a handpiece end to be coupled to a rotary tool in any position without risking disengagement of the flexible core member from the handpiece end.